JP4782209B2 - Power-saving monitoring device - Google Patents

Description

  The present invention relates to a technique for detecting the absence of a user using a distance sensor and performing power saving control of a monitor device.

  In Patent Document 1, in order to realize power saving of the mobile phone device, when the operation unit is not operated for a predetermined time, the distance sensor detects whether there is an object in the vicinity of the device. Based on this, it is disclosed to control on / off of the light source of the display unit (see paragraph 0097 of the original specification of cited document 1). That is, in the technique of Patent Document 1, the light source of the display unit is turned on when the distance to the user measured by the distance sensor is within a predetermined effective range, and the light source of the display unit is turned off when it is outside the effective range ( (See Cited Reference 1, Initial Specification 0085).

  Japanese Patent Laid-Open No. 2004-26853 discloses that a distance sensor is used to execute processing such as a screen shutter function when the operator determines that the operator has moved away from the apparatus, and when the operator has determined that the operator has moved in a direction approaching the apparatus. It is disclosed to control to cancel the execution (see paragraph 0027 of the original specification of cited document 2).

JP 2004-21306 A JP-A-11-95878

  However, there are individual differences in swinging movements such as back and forth movements and back stretching performed by humans. For this reason, in order to perform the transition to the power saving mode for any user without malfunction, it is necessary to change (update) the effective range serving as a reference for the mode transition determination according to the movement of each user. .

  The technique of Patent Document 1 describes the updating of the effective range. Specifically, the effective range is changed (shifted) by changing the distance serving as the reference of the effective range. However, changing the width (size) of the effective range is not considered, and the entire effective range can only be moved (shifted) forward or backward with respect to the user's longitudinal movement. The effective range cannot be changed.

  Further, in the technique of Patent Document 2, the transition to the power saving mode is not determined based on the effective range, and the power saving control is merely performed based on the direction of the user's operation. May cause a malfunction due to the fluctuation motion (breathing, back-and-forth motion, back extension, etc.)

  The present invention provides a determination numerical range (fluctuation range) that serves as a reference for determining the presence / absence of a monitor user on condition that the monitor user has returned to the determination numerical range within a predetermined time after being out of the determination numerical range. It is an object of the present invention to provide a high-accuracy power-saving monitoring device by updating to widen.

(1, 2) The power saving monitor device of the present invention is:
A distance sensor that is provided on the monitor and measures the distance to the user and outputs a signal,
Based on the signal received from the distance sensor, it is determined whether or not the distance to the user is out of the determination numerical value range, the determination means for outputting the result,
In response to the output from the determining means, the time measuring means for measuring that a predetermined time has elapsed since the distance to the user is out of the determination numerical range;
When the determination means determines that the distance to the user is out of the determination numerical range even after a predetermined time counted by the time measuring means from when the distance to the user is out of the determination numerical value range, the mode shifts to a predetermined power saving mode. Power control means for processing,
When the determination means determines that the distance to the user has not deviated from the determination numerical value range after a predetermined time counted by the time measuring means from when the distance to the user has deviated from the determination numerical value range, the width of the determination numerical value range is increased. Updating means for updating the determination numerical value range;
It is provided with.

  Accordingly, it is possible to flexibly and efficiently update the range of the determination numerical value range according to the user's movement, and it is possible to provide a monitor device capable of realizing higher power saving.

(3) The power saving monitoring device of the present invention is:
The updating means
By storing the distance the user is farthest from the distance sensor within the predetermined time after the distance to the user is out of the judgment numerical value range as a far threshold of the judgment numerical value range, in a direction to move away the judgment numerical value range. Expand and update, or
The direction in which the determination numerical value range is approached by storing the closest distance from the distance sensor within the predetermined time after the distance to the user is outside the determination numerical value range as a near threshold value of the determination numerical value range. Update to
It is characterized by that.

  As a result, according to the user's movement, the distance that the user is farthest away is updated as the far threshold of the judgment value range, or the distance that the user is closest is updated as the near threshold of the judgment value range Therefore, it is possible to provide a monitor device capable of realizing higher power saving.

(4) The power saving monitor device according to the present invention comprises:
The updating means updates the determination numerical value range by recalculating the determination numerical value range based on the average value of the distance to the user.
It is characterized by that.

  Thereby, it is possible to finely adjust the determination numerical value range, and it is possible to provide a monitor device capable of realizing extremely high power saving.

(5) The power saving monitor device according to the present invention comprises:
The updating means further comprises:
When the determination means determines that the distance to the user is within the determination numerical value range within a predetermined time, the distance that the user is farthest within the predetermined period is stored as a far threshold of the determination numerical range. Update to narrow the range of the judgment numerical value by or
If the determination means determines that the distance to the user is within the determination numerical range within a predetermined time, the determination numerical range is stored by storing the distance that the user is closest to as a near threshold of the determination numerical range Update to narrow the width of
It is characterized by that.

  As a result, in response to the user's movement, it is possible not only to update the range of the judgment numerical value range to be widened, but also to reduce the width of the judgment numerical value range when a predetermined condition is satisfied. A highly versatile power-saving monitor device can be provided.

(6) The power-saving monitoring device of the present invention comprises:
Based on the output from the distance sensor, comprising a still object determination means for determining whether the measurement object is a still object,
When it is determined that the still object determination unit is a still object, the power control unit performs a process of shifting from the normal mode to the power saving mode.
It is characterized by that.

  Accordingly, it is possible to prevent a still life (object) from being erroneously determined as an animal (human), and to provide a power saving monitor device that prevents a malfunction when shifting from the normal mode to the power saving mode. Is possible.

(7) The power saving monitoring device of the present invention is:
The still life determination means includes
Select the maximum and minimum values from multiple data indicating the distance to the user obtained from the output from the distance sensor,
Determining a predetermined still-life threshold by determining which of the plurality of predetermined numerical ranges the maximum value belongs to;
When the difference between the maximum value and the minimum value is larger than the determined predetermined still life threshold, it is determined that the measurement object is not a still object,
It is characterized by that.

  As a result, it is possible to prevent a still life (object) from being mistakenly determined to be an animal (human) using a plurality of still life thresholds, and to prevent malfunction during the transition from the normal mode to the power saving mode. It is possible to provide a power saving monitor device that is effectively prevented.

(8) The power saving monitor device according to the present invention comprises:
Based on the output from the distance sensor, it comprises an absence determination means for determining whether or not the measurement object has left,
When the absence determination unit determines that the distance measured by the distance sensor exceeds a predetermined separation threshold, the power control unit performs a process of shifting from the normal mode to the power saving mode.
It is characterized by that.

  Accordingly, it is possible to provide a power saving monitor device that can shift from the normal mode to the power saving mode when the user leaves the seat.

  In this embodiment, the “fluctuation range (determination value range)” determines whether or not the user is currently in front of the monitor on the assumption that the user in front of the monitor moves back and forth due to breathing, stretching, etc. 2 is a numerical range that is used in order to identify a range that is delimited by a far threshold (Dmax shown in FIG. 2A) and a near threshold (Dmin shown in FIG. 2A). The fluctuation range may be specified by at least one of the far threshold (Dmax shown in FIG. 2A) or the near threshold (Dmin shown in FIG. 2A). When the numerical range is specified only by Dmax), the fluctuation range is below the far threshold Dmax, and when the numerical range is specified only by the near threshold (Dmin shown in FIG. 2A). The fluctuation range is near the near threshold value Dmin.

  In this embodiment, the processing in steps S1207 and S1214 shown in FIG. 9 corresponds to the determination means, the processing in step S1213 shown in FIG. 9 corresponds to the power control means, and the processing in step S1210 shown in FIG. Corresponds to the updating means.

It is a block diagram of the power saving monitor apparatus of this invention. It is a schematic diagram (FIG. 2A) for demonstrating the concept of a fluctuation | variation range, and the graph (FIG. 2B) which shows a distance-output voltage characteristic. It is a figure which shows the hardware constitutions of the power saving monitor apparatus of this invention. It is a figure which shows the specific example of the data memorize | stored in power saving determination DB. It is a graph which shows the example of the distance data measured about a plurality of users. It is a flowchart which shows the content of the main process. It is a flowchart which shows the detail of the periodic process of normal mode. It is a flowchart which shows absence determination processing. It is a flowchart which shows a fluctuation determination process. It is a flowchart which shows the detail of a still-life determination process (S1300 of FIG. 9). It is a graph which shows the update method of a fluctuation range. It is a flowchart which shows the outline | summary of the periodic process of a power saving mode. It is a flowchart which shows the return process from a leaving seat sleep state. It is a flowchart which shows the return process from a still-life sleep state. It is a flowchart which shows the return processing from a fluctuation sleep state. It is a flowchart which shows the update process of the fluctuation range in other embodiment. It is a graph which shows the update method of the fluctuation range in other embodiment. It is a figure which shows the hardware constitutions in other embodiment.

[Block diagram of power saving monitor device 100]
A block diagram of the power saving monitor device 100 of the present invention is shown in FIG. As shown in FIG. 1, the power saving monitor device 100 includes a distance sensor 102, a determination numerical value range storage unit 104, a determination unit 106, a time measuring unit 108, a power control unit 110, and an update unit 112.

  FIG. 2A is a side view of the power saving monitor device 100. The PSD sensor 2 which is the distance sensor 102 is provided on the upper part of the monitor 6 as shown in FIG. 2A and is used for measuring the distance to the object. The PSD sensor 2 includes a light projecting element that emits light for measuring the distance to the user 3 and a light receiving element that receives reflected light from the object, and the PSD (infrared active) sensor 2 is used. Measure distance by triangulation method. However, if the distance to the object (user 3) can be measured, for example, a different type of sensor such as an ultrasonic sensor may be used.

  The user 3 shown in FIG. 2A manually operates the angle of the sensor 2 at the start of use of the monitor 6, the target point of the sensor 2 (the optical axis of the PSD sensor 2) is the height of the chest of the user 3, and the chest Adjust so that it is near the center of the. Thereby, the directional beam projected from the PSD sensor 2 can be reflected by the chest of the user 3 and received by the sensor 2. Note that the angle adjustment of the sensor 2 can be automatically performed.

  FIG. 2B is a diagram showing the relationship between the output voltage (vertical axis) of the PSD sensor 2 and the corresponding distance to the user 3 (horizontal axis). As shown in FIG. 2B, the output voltage of the PSD sensor 2 increases when the user 3 approaches the monitor 6, and the output voltage of the PSD sensor 2 decreases when the user 3 moves away from the monitor 6. The distance to the user 3 can be easily measured using such characteristics.

The determination numerical value range storage means 104 shown in FIG. 1 is a means for storing a near threshold value Dmin and a far threshold value Dmax (see FIG. 2A) for specifying the fluctuation range that is the determination numerical value range. As shown in FIG. 2A, the fluctuation range near threshold value Dmin is indicated by a position that is closer to the reference distance Dc by the near fluctuation width ΔD ^{− based on} the distance to the user 3 (reference distance Dc). It is. As shown in FIG. 2A, the far threshold Dmax of the fluctuation range is indicated at a position separated from the reference distance Dc by the far fluctuation width ΔD ⁺ with reference to the distance to the user 3 (reference distance Dc).

  The determination means 106 shown in FIG. 1 determines whether or not the distance to the user is out of the determination numerical value range (fluctuation range) based on the signal received from the distance sensor 102 (PSD sensor 2 shown in FIG. 2A). , Means for outputting the result.

  The time measuring means 108 shown in FIG. 1 has a timer function and receives an output from the determining means 106 and indicates that a predetermined time has elapsed since at least the distance to the user deviated from the determination numerical value range (fluctuation range). It is a means for timing.

  In the power control unit 110 shown in FIG. 1, the determination unit 106 determines whether the distance to the user 3 is out of the determination numerical value range (fluctuation range) after a predetermined time when the output from the time measuring unit 108 is received. This is a means for performing a process of shifting to a predetermined power saving mode when it is determined that the range (fluctuation range) is out of range.

  The update unit 112 shown in FIG. 1 is configured so that the determination unit 106 determines whether the distance to the user 3 is out of the determination numerical value range (fluctuation range) after a predetermined time after receiving the output from the time measuring unit 108. In the case where it is determined that the range is not out of the range, the update is performed so as to widen the range of the determination numerical value range (fluctuation range).

  With the above configuration, the power saving monitor device 100 according to the present invention saves power when the user 3 in front of the monitor 6 performs a fluctuation operation and moves out of the fluctuation range and returns to the fluctuation range within a predetermined time. The mode is updated to widen the fluctuation range without shifting to the mode, and when the user 3 does not return to the fluctuation range within a predetermined time after leaving the seat, the mode is shifted to the power saving mode.

  As described above, updating the width of the fluctuation range so as to widen it is possible to set the fluctuation range narrow in the initial state and gradually widen it according to the movement of the user 3 for any user. This is because the setting update process can be simplified.

[Example (when fluctuation range is within far threshold Dmax)]
An example in which the fluctuation range is specified only by the far threshold (Dmax shown in FIG. 2A) (that is, the fluctuation range is within the far threshold Dmax) will be described below. When the fluctuation range is specified only by the near threshold (Dmin shown in FIG. 2A) (that is, when the fluctuation range is equal to or greater than the near threshold Dmin), the fluctuation range is the far threshold (see FIG. 2). 2D) and the near threshold value (Dmin shown in FIG. 2A) (that is, when the fluctuation range is not less than the near threshold value Dmin and within the far threshold value Dmax), It can be implemented using a technique similar to the technique shown in this embodiment.

  FIG. 3 is a diagram showing a specific hardware configuration of the power saving monitor apparatus 100 of the present invention. As shown in FIG. 3, the power saving monitor device 100 includes a PSD sensor 2 mounted outside the housing, an MPU 4 mounted inside the housing, a monitor 6, a communication unit 8 that transmits and receives data to and from an external PC, and a memory 12, a user interface 14 such as a power button, and a timer 16 (seating timer 16a, still life timer 16b, fluctuation timer 16c).

  As shown in FIG. 3, in the memory 12, in addition to the power saving program 20 for performing power saving control, a distance calculation table 22 for calculating the distance from the output of the PSD sensor 2 (the distance-output voltage shown in FIG. 2B). A data table corresponding to a characteristic graph), data indicating a fluctuation range, a power saving determination DB 24 including various data used for calculation of the fluctuation range, and the like are recorded.

  FIG. 4 is a diagram illustrating an example of data stored in the power saving determination DB 24.

As shown in FIG. 4, the power saving determination DB 24 includes, for each user, a user ID, a reference distance Dc, a far threshold Dmax of the fluctuation range, a far fluctuation width ΔD ⁺ , and a provisional value Dtemp used for updating the fluctuation range. Measured value Da indicating the distance to the user measured by the PSD sensor 2 in the normal mode (for example, five values Da1 to Da5) and a primary average measured value Db calculated by averaging a predetermined number of measured values Da (For example, 20 of Db1 to Db20), a sleep flag indicating the type of the sleep state when the power saving mode is entered (the sleep sleep flag F1, the fluctuation sleep flag F2, and the still life sleep flag F3), power saving A power saving flag F0 indicating the transition to the mode, a measured value Da ′ (for example, 3 of Da1 ′ to Da3 ′) of the distance to the user measured in the power saving mode Etc.) are stored.

  The reference distance Dc shown in FIG. 4 is a value serving as a reference for calculating the far threshold Dmax of the fluctuation range. In this embodiment, as will be described later, when 20 primary average measured values Db are initially accumulated, a value obtained by averaging them (obtained from 5 × 20 = 100 measured values Da) is obtained. This is the initial value of the reference distance Dc.

  In FIG. 2A, for convenience of explanation, the distance from the sensor 2 to the target point is indicated by Dc (reference distance), but the reference distance Dc further includes a measurement value Db obtained by averaging real-time measurement values Da. The average value. For this reason, the distance to the target point in FIG. 2A that is the real-time measurement value Da does not exactly match the reference distance Dc.

The distance fluctuation width ΔD ^{+ in} FIG. 4 is data of a value indicating that the distance threshold Dmax is at a position (see FIG. 2A) that is apart from the reference distance Dc by ΔD ⁺ . That is, for example, as in the case of the user (ID “0001”) shown in FIG. 4, when the reference distance Dc is “75” cm and the far fluctuation width ΔD ⁺ is “15” cm, the far threshold Dmax in the fluctuation range. Is obtained from (Expression) Dmax = Dc + ΔD ⁺ with 75 + 15 = “90” (cm). In this case, the fluctuation range is specified as a numerical range of the far threshold Dmax “90” cm or less.

  The provisional value Dtemp shown in FIG. 4 is data that temporarily stores, for example, the measured value Db (maximum value) when the fluctuation value is out of the fluctuation range. For example, in the case of the user (ID “0001”) shown in FIG. 4, the measured value “93” cm when the numerical value range (fluctuation range) of the far threshold Dmax “90” cm or less is deviated as the provisional value Dtemp. It is remembered.

  The measured values Da (Da1 to Da5) shown in FIG. 4 are data obtained by accumulating values obtained by measuring with the PSD sensor 2 in the normal mode for the past five times. In this embodiment, the measurement value Da is used only for calculation of the measurement value Db, and is not used for determination processing such as fluctuation determination, absence determination, and still life determination.

  FIG. 5 is a graph showing changes in the measured value Da calculated by measuring the distance to the monitor over time for a plurality of users seated before the monitor. M1 and M2 are male data, and F1 and F2 are female data.

  From the graph shown in FIG. 5, the male user M2 moves more violently than the females F1, F2 and the male M1, and the male user M1 is relatively far away from the sensors 2 than the females F1, F2 and the male M2. You can see that you are in position. As described above, the intensity of movement and the average distance vary greatly among individuals, and it is highly significant to set and update the fluctuation range according to each user.

  The measured values Db (Db1 to Db20) shown in FIG. 4 are data obtained by accumulating the values obtained by averaging each time the measured values Da are accumulated five times for the past 20 times. The measured value Db is stored in a FIFO (first-in first-out) manner. Therefore, for example, when the number of stored measurement values Db exceeds 20, the old data Db20 is erased, and at the same time, the measurement values Db1 to Db19 are rewritten to the measurement values Db2 to Db20. That is, Db1 is always data in which the latest first average value is stored.

  The measured values Da ′ (Da1 ′ to Da3 ′) are data obtained by accumulating values obtained by measuring with the PSD sensor 2 in the power saving mode for the past three times. Note that the measured value Da 'in the power saving mode is stored in a FIFO (first in-first out) manner.

  In the power saving flag F0 of the power saving determination DB shown in FIG. 4, “1” is written when the mode is shifted to the power saving mode, and “0” is written in the normal mode. Based on the power saving flag F0, it can be determined whether the current mode is the power saving mode or the normal mode.

  In addition, each sleep flag of the power saving determination DB shown in FIG. 4 includes data corresponding to any one of the away sleep flag F1, the fluctuation sleep flag F2, and the still life sleep flag F3 when the mode is shifted to the power saving mode. “1” is written. In the normal mode, “0” is written in all. For example, when the fluctuation determination results in a fluctuation sleep state (power saving mode), data “1” is written in the fluctuation sleep flag F2.

[Processing executed by the power saving program 20]
FIG. 6 shows a flowchart of main processing executed by the power saving program 20 stored in the memory 12 of FIG.

As shown in FIG. 6, the power saving program 20 first has a predetermined period (period T _{1 in} the normal mode and period T _{1 in} the power saving mode) that differs depending on whether the current mode is the normal mode or the power saving mode. The main process is started every time the mode T _{2 is} set in advance (step S100).

Specifically, when "0" to the power-saving flag F0 is stored, it starts the main process at every predetermined time T _1. Meanwhile, when "1" to the power-saving flag F0 power saving determination DB24 is stored, it starts the main process at every predetermined time T _2.

Period _T 1, _{T 2} executing the main process, for example, the period _T 1 = 100 m sec every normal mode, as such period _T 2 = every second power saving mode, saving than the period _{T 1} of the normal mode Although better period T ₂ of the power mode is set to be longer, this is to reduce power consumption in the power saving mode.

  Further, depending on whether the current mode is the normal mode or the power saving mode (step S200), the MPU 4 performs a predetermined periodic process in the normal mode (step S1000, which will be described in detail in FIGS. 7 to 10). In the power saving mode, a predetermined periodic process (step S2000) is executed.

[Periodic processing in normal mode]
First, details of the normal mode periodic processing (step S1000) shown in FIG. 6 will be described using the flowcharts shown in FIGS.

  FIG. 7 is a flowchart showing the processing from the start of the measurement of the distance to the user until the fluctuation range is calculated and set. FIG. 8 is a flowchart showing an absence determination process for determining whether or not the user has left after the process shown in FIG. 7. FIG. 9 is a flowchart showing details of the fluctuation determination process for determining whether the user is out of the fluctuation range after the process shown in FIG. FIG. 10 is a flowchart showing details of the still object determination process (step S1300 in FIG. 9) for determining whether or not the detected object is a still object (object).

  As shown in FIG. 7, first, the MPU 4 refers to the distance calculation table 22 based on the output of the sensor 2, and stores the obtained measurement value Da in the power saving determination DB 24 (step S1001).

When a predetermined number N ₁ , for example, five measurement values Da are accumulated (Yes in step S1002), the value obtained by calculating the average is stored as the measurement value Db, and all the data (5) of the measurement values Da are deleted. (Step S1003). For example, the average of five data “67.2,..., 76.1” of the measurement value Da (1-5) shown in FIG. 4 is calculated to obtain the measurement value Db1 “73.1”. .

  In step S1003, the measurement value Db is calculated every time five pieces of data of the measurement value Da are accumulated. However, the measurement value Db is obtained for each period in which one piece of data of the measurement value Da is obtained (that is, by moving average). May be calculated. In this case, since the data of the measured value Da is stored by the FIFO method, the data of the measured value Da is deleted one by one from the oldest one in each cycle.

  Further, the normal mode periodic process is looped from the beginning until 20 pieces of measured value Db data are accumulated (step S1004). Since the fluctuation range is not yet set until 20 pieces of measured value Db data are accumulated, the power saving determination process is not performed.

When a predetermined number N ₂ (for example, 20) is accumulated for the first time (for example, 20 in step S1005), the MPU 4 calculates the average of the measured values Db and stores the obtained value as the reference distance Dc. At the same time, the fluctuation range is calculated based on the reference distance Dc (step S1006). Specifically, the far threshold Dmax (= Dc + ΔD ⁺ ) of the fluctuation range is calculated, and the fluctuation range is set.

Here, a value set in advance is used as the distance fluctuation width ΔD ⁺ . For example, as shown in FIG. 4, when the distance fluctuation width ΔD ⁺ is set to “15” cm in advance and the calculated reference distance Dc is “75” cm, the distance threshold Dmax of the fluctuation range is set. “90” cm (= 75 + 15) is calculated and stored in the power saving determination DB 24.

When the setting of the fluctuation range is completed, the absence determination process (step S110 shown in FIG. 8).
1 to S1105) are performed.

  As shown in FIG. 8, the MPU 4 determines whether or not the measured value Db (calculated in step S1003) exceeds a predetermined away threshold Df (for example, set to 120 cm) (step S1101). As a result, when the away threshold Df is not exceeded (that is, when the away threshold Df is less than or equal to), the away timer 16a is reset to 0 (step S1105), and the fluctuation determination described later is performed. The process proceeds to (FIG. 9).

  When the MPU 4 determines that the measured value Db exceeds the predetermined leaving threshold Df (Yes in step S1101), the MPU 4 counts up the leaving timer 16a and resets the fluctuation timer 16c to 0 (step S1102). ). Here, the reason why the fluctuation timer 16c is reset to 0 is because the case where the fluctuation timer 16c is counted up in the previous periodic process is taken into consideration.

  Further, when the measured value Db exceeds the away threshold value Df even after a predetermined away time-out time t0 (for example, arbitrarily set between 2 seconds and 5 seconds) has elapsed (Yes in step S1103). The MPU 4 writes “1” in the away sleep flag F1 and “1” in the power saving flag F0 of the power saving determination DB 24 (step S1104), and shifts to the power saving mode in the next cycle (FIG. 6). Steps S100, S200, S2000).

  Until the predetermined time-out value t0 elapses (No in step S1103), the processing from step S1001 in FIG. 7 to step S1103 in FIG. 8 is repeated in the subsequent periodic processing.

  As described above, when the user in front of the monitor leaves the seat, the user enters the sleep sleep state and shifts from the normal mode to the power saving mode. Is performed (shown in step S2100 in FIG. 12).

  After the absence determination process (steps S1101 to S1105) shown in FIG. 8, the MPU 4 determines whether or not the fluctuation timer 16c has passed a predetermined time t1 (for example, 1.5 seconds) (step S1201).

  However, when step S1201 is first reached in the periodic processing in the normal mode, the fluctuation timer 16c has not yet been counted up. For this reason, the process proceeds to step S1202 without moving to the fluctuation determination process (step S1203), and the still object determination process (step S1300) is performed.

After step S1201 shown in FIG. 9, the MPU 4 calculates the reference distance Dc before the still-life determination process (step S1300) and adjusts and updates the fluctuation range (step S1202). For example, the reference distance Dc is obtained by averaging the 20 measured values Db as described above (that is, the second average of the measured values Da), and the obtained reference distance Dc and the power saving determination Based on the value of the distance fluctuation width ΔD ⁺ stored in the DB 24, the distance threshold Dmax in the fluctuation range is newly calculated from (Expression) Dmax = Dc + ΔD ⁺ , and is rewritten and stored.

  Note that after the fluctuation range is initially set in step S1006, the measured value Db is set in step S1202 or step 1204 described later until the fluctuation range is updated to expand based on the provisional value at the time of deviation from the fluctuation in step S1210. It is adjusted and updated based on the reference distance Dc obtained by averaging.

  When the fluctuation range is updated in step S1202, a still object determination process (step S1300) is performed as shown in FIG. FIG. 10 is a diagram showing the details of the still object determination process (step S1300 in FIG. 7).

  As shown in FIG. 10, in still-life determination, first, the measured value Db is smaller than a predetermined proximity threshold value Dn by referring to the power saving determination DB 24 (that is, the user is closer to the predetermined proximity threshold value Dn). Is determined) (step S1301).

  If the measured value Db is within the proximity threshold value Dn and the distance to the user is too close (for example, 30 cm or less), the still-life timer 16b is reset to 0 (step S1308), and the still-life determination process ends. This is because if the distance to the sensor is too close, the sensitivity will be significantly reduced. Thereafter, the process proceeds to a fluctuation determination step (step S1214) described later.

When the MPU 4 determines that the measured value Db is not within the predetermined proximity threshold value Dn, as shown in FIG. 8, only the predetermined number N _{3 of the} latest measured value Db data from the power saving determination DB 24 is obtained. The maximum value and the minimum value are selected from among the read values (step S1302). For example, when three measured values Db of Db1, Db2, and Db3 are read and each value is “40” cm for Db1, “50” cm for Db2, and “60” cm for Db3, Db3 is the maximum value. Db1 is selected as the minimum value.

  Furthermore, whether the selected maximum value data belongs to the numerical range R1 [0 to r1], R2 [r1 to r2], or R3 [r2 or more] (for example, r1 = 70 cm, r2 = 85 cm). Judgment is made (step S1303).

  As a result, when the maximum value is in the range of R1 [0 to r1], s1 (for example, 2 cm) is set as the still life threshold value S (step S1304). When the maximum value is in the range of R2 [r1 to r2], s2 (for example, 3 cm) is set as the still life threshold (step S1305). When the maximum value is in the range of R3 [r2 to greater than or equal to], s3 (for example, 4 cm) is set as the still life threshold (step S1306).

  For example, when the maximum value is “60” cm, since it belongs to the numerical value range R1, the still-life threshold value S is s2 = 3 cm. Each value (s1, s2, s3) of the still life threshold value S is set in advance as a still life threshold value corresponding to each numerical value range.

  In this way, the reason why the still object threshold value is set stepwise in accordance with the distance to the object is because the measurement accuracy of the sensor decreases as the distance from the object increases. In this embodiment, the still-life threshold value is set stepwise by three candidate values, but may be set by a value calculated as a percentage ratio to the maximum measured value Db.

  After deciding the still life threshold value S, the MPU 4 determines whether the difference between the minimum value and the maximum value of the measured value Db is larger than the still life threshold value S (s1, s2, s3) (step S1307). When the difference between the minimum value and the maximum value of the measured value Db is larger than the still life threshold value S (s1, s2, s3) (Yes in step S1307), as shown in FIG. 10, the still life timer 16b is reset to 0 ( Step S1308) is followed by the fluctuation determination step (step S1214 in FIG. 9).

  When the difference between the minimum value and the maximum value of the measured value Db is larger than the still life threshold value S (s1, s2, s3) (Yes in step S1307), the still life timer 16b is counted up (step S1309). For example, when Db3 “60” is selected as the maximum value and Db1 “58” is selected as the minimum value, the difference “2” cm (= 60−58) is smaller than the still life threshold S (s2 = 3 cm). Therefore, the still life timer 16b is counted up.

  In the subsequent periodic processing, when the difference between the minimum value and the maximum value of the measured value Db is smaller than the still life threshold value S (s1, s2, s3) even after a predetermined time t5, for example, 45 seconds, (step S1311) Yes), the MPU 4 controls to decrease the brightness of the panel for a predetermined time ts seconds (step S1312).

  Further, if the difference between the minimum value and the maximum value of the measured value Db is smaller than the still life threshold value S (s1, s2, s3) even after a predetermined time t4, for example 60 seconds (> t5), (step) In step S1310, “1” is written in the still life sleep flag F3 and “1” is written in the power saving flag F0 (step S1313), and the mode is shifted to the power saving mode (steps S100, S200, and S2000 in FIG. 6). ).

  As described above, when it is determined that the detected object is a still object, it enters the still object sleep state and shifts from the normal mode to the power saving mode. Return processing (step S2200 in FIG. 12) is performed.

  As shown in FIG. 9, after the still object determination (S1300 in FIG. 9), a fluctuation determination process is performed (step S1214). Specifically, it is determined whether or not the measured value Db (nearest Db1) is out of the fluctuation range (below the far threshold Dmax).

  As a result, when it is determined that the measured value Db is out of the fluctuation range (below the far threshold Dmax) (Yes in step S1214), the fluctuation timer 16c is counted up and the fluctuation range shown in FIG. The measured value Db at the time of deviating is stored as the provisional value Dtemp (step S1215).

  FIG. 11 is a graph for explaining a fluctuation range update method. As shown in FIG. 11, the count-up is started when the far threshold Dmax is exceeded.

  When the fluctuation timer 16 is counted up (step S1215 in FIG. 9), and it is determined that the fluctuation range is out of range even if a predetermined timeout time t1 (for example, 1.5 seconds) elapses in the subsequent period. (Yes in step S1201), the above-described still-life determination (step S1300) is not performed, and the process proceeds to the fluctuation determination process. In other words, the still life determination is performed until the predetermined time t1 elapses after the fluctuation range is removed.

  Further, in a subsequent cycle, the fluctuation range is continuously updated (step S1204) until a predetermined timeout time t2 (for example, 3 seconds) elapses (step S1203). This is to prevent the fluctuation range from spreading more than necessary until the measured value settles, even when the fluctuation range steeply leaves.

  In the subsequent cycle, the count-up (step S1206) is performed until the predetermined timeout time t3 has elapsed, and the MPU 4 further determines whether or not the fluctuation range has been returned (step S1207).

When returning to the fluctuation range, the fluctuation timer 16c is reset to 0 (step S1208), and the fluctuation range is updated with the stored provisional value Dtemp (step S1210). Specifically, the far threshold value Dmax is rewritten to the provisional value Dtemp, and further, based on the far threshold value Dmax and the value of the reference distance Dc, the distance fluctuation width ΔD from (Expression) ΔD ⁺ = Dmax−Dc ^A new ⁺ value is calculated and rewritten. Note that the value of the reference distance Dc is not rewritten here.

That is, as shown in FIG. 11, when a predetermined time t3 has elapsed after leaving the fluctuation range, the far threshold of the fluctuation range changes from Dmax (for example, “90” cm) to Dmax ′ (for example, “93” cm). Updated to spread. As a result, the value of the distance fluctuation width ΔD ⁺ increases by the distance threshold difference (Dmax′−Dmax) (for example, “3” cm).

  On the other hand, when the measured value Db does not return to the fluctuation range, only when the measured value Db is larger than the provisional value Dtemp (Yes in step S1211), the data of the provisional value Dtemp is rewritten with the measured value Db at the time of deviation ( Step S1212).

  When a predetermined time t3 (for example, 5 seconds) elapses, “1” is written in the fluctuation sleep flag F2 and “1” is written in the power saving flag F0 of the power saving determination DB 24 shown in FIG. 4 (step S1213). The mode is shifted to the power saving mode (steps S100, S200, and S2000 in FIG. 6).

  As described above, when the user is out of the fluctuation range and satisfies a predetermined condition, the fluctuation sleep state is entered and the normal mode is shifted to the power saving mode, and the power saving mode is periodically processed as described later. , A process for returning from the fluctuation sleep state (shown in step S2300 in FIG. 12) is performed.

[Periodic processing in power saving mode]
Next, a return process performed when the mode is shifted to the power saving mode will be described below with reference to FIGS. FIG. 12 is a flowchart showing periodic processing in the power saving mode. FIG. 13 is a flowchart showing details of the return processing from the away-sleep state, FIG. 14 from the still-life sleep state, and FIG. 15 from the fluctuation sleep state.

When the mode is shifted to the power saving mode, “1” is stored in the power saving flag F0 of the power saving determination DB 24. Therefore, in the main processing shown in FIG. 6, MPU 4 is now, it is determined that the power saving mode starts processing at every predetermined time T _2, based on this, the periodic processing of the power saving mode (FIG. 6 steps S200 and S2000) are executed.

  In the periodic processing in the power saving mode, first, as shown in FIG. 12, the value of the distance to the user is acquired by referring to the distance calculation table 22 (FIG. 3) from the output of the sensor 2, and FIG. The value obtained in the power saving determination DB 24 shown is stored as the measured value Da ′ (step S2001). In addition, unlike the periodic process in the normal mode, the periodic process in the power saving mode calculates an average of measured values (data corresponding to the measured value Db of the primary average in FIG. 4) in order to suppress power consumption. Not.

  Further, the MPU 4 refers to the power saving determination DB 24 to determine which type of sleep state it is currently in (step S2002 in FIG. 12), and indicates a flag indicating each sleep state (separated sleep flag F1, fluctuation sleep). The return processing (any of S2100, S2200, and S2300 in FIG. 12) corresponding to each of the flag F2 and the still-life sleep flag F3) is executed.

  That is, when the absence sleep sleep state is shifted to the power saving mode ("1" is stored in the away sleep flag F1), the return process from the away sleep state shown in FIG. 13 is executed. (Step S2100). The details of the return processing from the away-sleep state (S1104 in FIG. 8) will be described below with reference to FIG.

  In the return processing from the away from sleep state, the MPU 4 determines whether or not the measured value Da ′ exceeds a predetermined away threshold value Df ′ as shown in FIG. It is determined whether it has returned (step S2101). When the measured value Da ′ exceeds the away threshold value Df ′, that is, when it is determined that the user has not left the seat and has not returned to the monitor (Yes in step S2101), the cycle of the power saving mode Move to the next loop.

  On the other hand, when the measured value Da ′ does not exceed a predetermined leaving threshold Df ′ (for example, set to the same value as the leaving threshold Df in the normal mode), that is, it is determined that the user has returned before monitoring In (No in step S2101), the MPU 4 counts up the away timer 16a (step S2102).

  Further, when the predetermined time-out time t0 ′ elapses with the measured value Da ′ being equal to or less than the away threshold Df ′ (Yes in step S2103), the MPU 4 turns off the away sleep state (seated sleep flag F1). "0" is written in), and the normal mode is entered ("0" is written in the power saving flag F0) (step S2104).

  Thereby, the periodic process in the normal mode (shown in the flowcharts in FIGS. 6 to 8) is selected and executed in the main process. The predetermined time-out time t0 'is set to, for example, 1.5 seconds, which is shorter than t0 in the normal mode (for example, arbitrarily set between 2 seconds and 5 seconds).

  As described above, when the user is seated in the power saving mode, the mode is shifted from the power saving mode to the normal mode.

  Next, the return processing from the still life sleep state (S1313 in FIG. 10) will be described with reference to FIGS.

When the measured value Da ′ of the distance to the user (obtained at step 2001 in FIG. 12) is accumulated by a predetermined number N ₄ , for example, 3 or more (Yes in step S2201 in FIG. 14), the MPU 4 first selects these measured values Da. It is determined whether 'is smaller than a predetermined short distance threshold value Dn' (step S2202). When it is determined that these measured values Da ′ are smaller than the predetermined short-distance threshold value Dn ′ (Yes in step S2202), the MPU 4 sets “0” in the still life sleep flag F3 and “0” in the power saving flag F0. Is written (step S2205), and the normal mode is entered in the next cycle (steps S100, S200, and S2000 in FIG. 6).

If the measured value Da ′ is not too close to the predetermined short-range threshold value Dn ′, a predetermined number N ₄ (for example, three) of the three most recent data of the measured value Da ′ is read, and the maximum value and the minimum value are obtained. Selection is made (step S2203).

  Further, it is determined whether the difference between the minimum value and the maximum value of the measured value is larger than a predetermined still life threshold value S ′ (step S2204), and the difference between the minimum value and the maximum value of the measured value is a predetermined still life threshold value S ′. If it is determined that it is greater than (the detection target has a motion) (Yes in step S2204), “0” is written in the still life sleep flag F3 and “0” is written in the power saving flag F0 (step S2205). Then, the normal mode is entered in the next cycle (steps S100, S200, S2000 in FIG. 6).

  On the other hand, if it is determined that the difference between the minimum value and the maximum value of the measured value is not larger than the predetermined still-life threshold value S ′ (the object to be detected does not move) (No in step S2204), the process proceeds to the normal mode. Without moving to the next loop (periodic processing in the power saving mode).

  As described above, when it is determined that the user is not a still life in the power saving mode, the mode is shifted from the power saving mode to the normal mode.

  Next, the return processing from the fluctuation sleep state (S1213 in FIG. 9) will be described with reference to FIGS.

  When the fluctuation sleep state is entered, after the measurement value Da ′ of the distance to the user is stored as shown in FIG. 12 in the periodic process in the power saving mode (S2001), the return process corresponding to the fluctuation sleep state shown in FIG. (S2002, S2300).

  If the measured value Da ′ does not return within the fluctuation range (No in step S2301), the MPU 4 resets the fluctuation timer 16c to 0 and proceeds to the next loop (periodic processing in the power saving mode) (step S2302). ). For the determination of the fluctuation range in step S2301, the fluctuation range in the normal mode before entering the power saving mode is used as it is.

  On the other hand, when the measured value Da ′ is within the fluctuation range (Yes in step S2301), the MPU 4 counts up the fluctuation timer 16c (step S2303). The process proceeds to the next loop until the fluctuation timer 16c exceeds the predetermined time t3 '(No in step S2304).

  Further, when the fluctuation timer 16c exceeds the predetermined time t3 ′ (Yes in step S2304), “0” is written in the fluctuation sleep flag F2 and “0” is written in the power saving flag F0 (step S2305). Shifts to the normal mode at the cycle (steps S100, S200, S2000 in FIG. 6).

  As described above, when a predetermined condition is satisfied, such as returning to the fluctuation range in the power saving mode, the mode is shifted from the power saving mode to the normal mode.

[Other Embodiments]
In the above embodiment, the fluctuation range is adjusted before updating. However, the fluctuation range may not be adjusted. Specifically, in FIG. 9, the processes in steps S1202 and S1204 may be deleted. Thus, the fluctuation range is changed only in step S1210 shown in FIG.

  In the above embodiment, in step S1210 of FIG. 9, the fluctuation range is updated so as to be always widened. However, when a predetermined condition is satisfied, the fluctuation range may be updated.

  FIG. 16 is a flowchart showing a process for updating so as to narrow the fluctuation range. The flowchart shown in FIG. 16 shows processing added after step S1214 in FIG. FIG. 17 is a graph showing a method for updating the fluctuation range shown in FIG.

  After the still object determination process (step S1300 in FIG. 9) is performed, the MPU 4 determines whether the measurement value Db is out of the fluctuation range (step S1214).

  As a result, if it is out of the fluctuation range (Yes in step S1214), as described above, the fluctuation timer 16c is counted up, the measurement value Db at the time of deviation is stored, and the process proceeds to the next loop (step S1215). .

  On the other hand, if the fluctuation range is not deviated (No in step S1214), the timer 16 different from the fluctuation timer 16c is counted up, and the maximum value (smaller than the far threshold Dmax) of the past measurement values Db. Is stored in the power saving determination DB as a provisional value Dtemp (step S1216).

Further, if the fluctuation range has not been exceeded even after a predetermined timeout time t6 has elapsed from the start of the fluctuation determination (Yes in step S1217), the MPU 4 resets the timer 16 to 0 (step S1218), and the provisional value Dtemp is used. The fluctuation range is updated (step S1219). Specifically, the far threshold value Dmax is rewritten to the provisional value Dtemp (less than the far threshold value Dmax), and further, based on the far threshold value Dmax and the reference distance Dc, (formula) ΔD ⁺ = New value of distance fluctuation width ΔD ⁺ is calculated from Dmax−Dc and rewritten. Note that the value of the reference distance Dc is not rewritten here.

That is, as shown in FIG. 17, when a predetermined time t6 has elapsed from the start of the fluctuation determination, the far threshold of the fluctuation range is updated so as to be narrowed from Dmax to Dmax ″. As a result, the value of the distance fluctuation width ΔD ⁺ decreases by the distance threshold difference (Dmax−Dmax ″).

  In the above embodiment, the processing by the power saving control program 20 stored in the memory 12 as shown in FIG. 3 is executed by the MPU 4 or the like inside the monitor device, but connected to the monitor 6 as shown in FIG. The power saving program 20 or the like may be stored in the hard disk 13 of the PC 200, and the power saving control program 20 may be executed by the CPU 5 on the PC 200 side.

  FIG. 18 is a diagram showing a specific hardware configuration of the power saving control PC 200 of the present invention. As shown in FIG. 18, the power saving control PC 200 connected to the external PSD sensor 2 and the monitor 6 includes a communication unit 8 that transmits and receives data to and from the CPU 5, the RAM 13, the monitor 6, the hard disk 13, the keyboard / mouse 15, A timer 16 is provided. The monitor 6 and the PC 200 are connected so that data can be exchanged by a wired method or a wireless method such as a USB or a dedicated cable (DDC / CI standard).

  In the hard disk 13 of FIG. 18, as in the memory 12 shown in FIG. 3, a power saving program 20 for performing monitor power saving control, and a distance calculation table 22 for calculating a distance based on the output from the PSD sensor 2. (A data table corresponding to the distance-output voltage characteristic graph shown in FIG. 2B), a power saving determination DB 24 (FIG. 4) storing data used for power saving control determination, fluctuation range calculation, and the like are recorded. .

  In the above embodiment, the power source 18 of the monitor 6 is controlled to save power. However, the power source 18 of the PC 200 (FIG. 18) connected to the monitor 6 may be controlled to save power. Further, the power supply 18 of both the monitor 6 and the PC 200 may be subjected to power saving control.

  In the above embodiment, in the power saving mode, the power saving control is performed by extending the time period of measurement by the sensor. However, other processing (for example, activation of a screen saver, shutdown of the PC, CPU to The power saving control may be performed by stopping the power supply.

  In the above embodiment, the still-life determination process (FIG. 10) is incorporated as the step S1300 in the fluctuation determination process shown in FIG. 9, but the still-life determination process is performed before the fluctuation determination process shown in FIG. May be.

  In the above embodiment, processing is performed by a special monitor device that performs power saving control. However, the above power saving control is realized by connecting a module for performing power saving control to a general-purpose monitor device. Also good.

  In the above embodiment, the still-life determination is performed by comparing whether or not the difference between the maximum value and the minimum value selected from the past measurement values Db is within a predetermined value (step in FIG. 9). In step S <b> 1307, it may be determined whether the object is still or not by constantly monitoring the AC component (analog waveform) of the output from the PSD sensor 2 using other methods.

  In the above-described embodiment, the PSD sensor 2 is provided on the upper part of the monitor 6. Alternatively, in the above embodiment, only one PSD sensor 2 is provided, but a plurality of PSD sensors 2 may be provided.

  In the above embodiment, in addition to the fluctuation determination (FIG. 9), the absence determination (FIG. 8) and the still life determination (FIG. 10) are performed, but these determination processes may be omitted.

DESCRIPTION OF SYMBOLS 100 ... Power-saving monitoring apparatus 102 ... Distance sensor 104 ... Determination numerical range storage means 106 ... Determination means 108 ... Time measuring means 110 ... Power control means 112- ... Update means

Claims (11)

A distance sensor that is provided on the monitor and measures the distance to the user and outputs a signal,
Based on the signal received from the distance sensor, it is determined whether or not the distance to the user is out of the determination numerical value range, the determination means for outputting the result,
In response to the output from the determining means, the time measuring means for measuring that a predetermined time has elapsed since the distance to the user is out of the determination numerical range;
When the determination means determines that the distance to the user is out of the determination numerical range even after a predetermined time counted by the time measuring means from when the distance to the user is out of the determination numerical value range, the mode shifts to a predetermined power saving mode. Power control means for processing,
When the determination means determines that the distance to the user has not deviated from the determination numerical value range after a predetermined time counted by the time measuring means from when the distance to the user has deviated from the determination numerical value range, the width of the determination numerical value range is increased. Updating means for updating the determination numerical value range;
A power saving monitor device comprising: Computer
A determination means for determining whether the distance to the user is out of the determination numerical value range based on a signal received from a distance sensor that measures the distance to the user and outputs a signal, and outputs the result.
In response to the output from the determining means, the time measuring means for measuring that a predetermined time has elapsed since the distance to the user is out of the determination numerical range;
When the determination means determines that the distance to the user is out of the determination numerical range even after a predetermined time counted by the time measuring means from when the distance to the user is out of the determination numerical value range, the mode shifts to a predetermined power saving mode. Power control means for processing,
When the determination means determines that the distance to the user has not deviated from the determination numerical value range after a predetermined time counted by the time measuring means from when the distance to the user has deviated from the determination numerical value range, the width of the determination numerical value range is increased. Updating means for updating the determination numerical value range;
Power-saving program for monitoring to function as In the power saving monitor device or the power saving program for monitoring according to claim 1 or 2,
The updating means includes
By storing the distance the user is farthest from the distance sensor within the predetermined time after the distance to the user is out of the judgment numerical value range as a far threshold of the judgment numerical value range, in a direction to move away the judgment numerical value range. Expand and update, or
The direction in which the determination numerical value range is approached by storing the closest distance from the distance sensor within the predetermined time after the distance to the user is outside the determination numerical value range as a near threshold value of the determination numerical value range. Update to
A power saving monitor apparatus or a power saving program for monitoring. In the power saving monitor device or the power saving program for monitoring according to any one of claims 1 to 3,
The updating means updates the determination numerical value range by recalculating the determination numerical value range based on the average value of the distance to the user.
A power saving monitor apparatus or a power saving program for monitoring. In the power-saving monitoring device or the power-saving program for monitoring according to any one of claims 1 to 4,
The updating means further includes:
When the determination means determines that the distance to the user is within the determination numerical value range within a predetermined time, the distance that the user is farthest within the predetermined period is stored as a far threshold of the determination numerical range. Update to narrow the range of the judgment numerical value by or
If the determination means determines that the distance to the user is within the determination numerical range within a predetermined time, the determination numerical range is stored by storing the distance that the user is closest to as a near threshold of the determination numerical range Update to narrow the width of
A power saving monitor apparatus or a power saving program for monitoring. In the power saving monitoring device or the power saving program for monitoring according to any one of claims 1 to 5,
Based on the output from the distance sensor, comprising a still object determination means for determining whether the measurement object is a still object,
When it is determined that the still object determination unit is a still object, the power control unit performs a process of shifting from the normal mode to the power saving mode.
A power saving monitor apparatus or a power saving program for monitoring. In the power saving monitor device or the power saving program for monitoring according to claim 6 ,
The still life determination means includes
Select the maximum and minimum values from multiple data indicating the distance to the user obtained from the output from the distance sensor,
Determining a predetermined still-life threshold by determining which of the plurality of predetermined numerical ranges the maximum value belongs to;
When the difference between the maximum value and the minimum value is greater than the predetermined still life threshold, it is determined that the measurement target is not a still life,
A power saving monitor apparatus or a power saving program for monitoring. In the power saving monitoring device or the power saving program for monitoring according to any one of claims 1 to 7,
Based on the output from the distance sensor, it comprises an absence determination means for determining whether or not the measurement object has left,
When the absence determination unit determines that the distance measured by the distance sensor exceeds a predetermined separation threshold, the power control unit performs a process of shifting from the normal mode to the power saving mode.
A power saving monitor apparatus or a power saving program for monitoring. A distance sensor that measures the distance to the user and outputs a signal,
Based on the signal received from the distance sensor, it is determined whether or not the distance to the user is out of the determination numerical value range, the determination means for outputting the result,
In response to the output from the determining means, the time measuring means for measuring that a predetermined time has elapsed since the distance to the user is out of the determination numerical range;
When the determination means determines that the distance to the user is out of the determination numerical range even after a predetermined time counted by the time measuring means from when the distance to the user is out of the determination numerical value range, the mode shifts to a predetermined power saving mode. Power control means for processing,
When the determination means determines that the distance to the user has not deviated from the determination numerical value range after a predetermined time counted by the time measuring means from when the distance to the user has deviated from the determination numerical value range, the width of the determination numerical value range is increased. Updating means for updating the determination numerical value range;
A power-saving device comprising: A distance sensor that is provided on the monitor and measures the distance to the user and outputs a signal,
Based on the signal received from the distance sensor, it is determined whether or not the distance to the user is out of the determination numerical value range, the determination means for outputting the result,
In response to the output from the determining means, the time measuring means for measuring that a predetermined time has elapsed since the distance to the user is out of the determination numerical range;
When the determination means determines that the distance to the user is out of the determination numerical range even after a predetermined time counted by the time measuring means from when the distance to the user is out of the determination numerical value range, the mode shifts to a predetermined power saving mode. Power control means for processing,
When the determination means determines that the distance to the user has not deviated from the determination numerical value range after a predetermined time counted by the time measuring means from when the distance to the user has deviated from the determination numerical value range, the width of the determination numerical value range is increased. Updating means for updating the determination numerical value range;
A power saving module for a monitor characterized by comprising: A distance sensor provided on the monitor measures the distance to the user and outputs a signal;
A step in which the computer determines whether the distance to the user is out of the determination numerical range based on a signal received from the distance sensor, and outputs the result;
Step a computer, measures that distance to the user a predetermined time elapses from the time an off-judgment value range,
A step of performing a process of shifting to a predetermined power saving mode when the computer determines that the distance to the user is outside the determination numerical range even after a predetermined time from when the distance is outside the determination numerical range;
A step of updating the determination numerical range to widen the determination numerical range when the computer determines that the distance to the user is not out of the determination numerical range after a predetermined time from when the distance is outside the determination numerical range;
A method of controlling a power saving monitor, comprising:

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